In vivo biocompatibility of porous silicon biomaterials for drug delivery to the heart

MicroRNA delivery based on nanoparticles of cardiovascular diseases

Cardiovascular disease, especially myocardial infarction, is a serious threat to human health. Many drugs currently used cannot achieve the desired therapeutic effect due to the lack of selectivity. With the in-depth understanding of the role of microRNA (miRNA) in cardiovascular disease and the wide application of nanotechnology, loading drugs into nanoparticles with the help of nano-delivery system may have a better effect in the treatment of cardiomyopathy. In this review, we highlight the latest research on miRNAs in the treatment of cardiovascular disease in recent years and discuss the possibilities and challenges of using miRNA to treat cardiomyopathy. Secondly, we discuss the delivery of miRNA through different nano-carriers, especially inorganic, polymer and liposome nano-carriers. The preparation of miRNA nano-drugs by encapsulating miRNA in these nano-materials will provide a new treatment option. In addition, the research status of miRNA in the treatment of cardiomyopathy based on nano-carriers is summarized. The use of this delivery tool cannot only realize therapeutic potential, but also greatly improve drug targeting and reduce side effects.

Nanowired human cardiac organoid transplantation enables highly efficient and effective recovery of infarcted hearts

Human cardiac organoids hold remarkable potential for cardiovascular disease modeling and human pluripotent stem cell-derived cardiomyocyte (hPSC-CM) transplantation. Here, we show cardiac organoids engineered with electrically conductive silicon nanowires (e-SiNWs) significantly enhance the therapeutic efficacy of hPSC-CMs to treat infarcted hearts. We first demonstrated the biocompatibility of e-SiNWs and their capacity to improve cardiac microtissue engraftment in healthy rat myocardium. Nanowired human cardiac organoids were then engineered with hPSC-CMs, nonmyocyte supporting cells, and e-SiNWs. Nonmyocyte supporting cells promoted greater ischemia tolerance of cardiac organoids, and e-SiNWs significantly improved electrical pacing capacity. After transplantation into ischemia/reperfusion-injured rat hearts, nanowired cardiac organoids significantly improved contractile development of engrafted hPSC-CMs, induced potent cardiac functional recovery, and reduced maladaptive left ventricular remodeling. Compared to contemporary studies with an identical injury model, greater functional recovery was achieved with a 20-fold lower dose of hPSC-CMs, revealing therapeutic synergy between conductive nanomaterials and human cardiac organoids for efficient heart repair.

BMSC exosome-enriched acellular fish scale scaffolds promote bone regeneration

Tissue engineering scaffolds are essential for repairing bone defects. The use of biomimetic scaffolds for bone tissue engineering has been investigated for decades. To date, the trend in this area has been moved toward the construction of biomimetic acellular scaffolds with effective modification to enhance the osteogenic differentiation efficiency of bone marrow mesenchymal stem cells (BMSCs). The exosomes derived from BMSCs have been shown as a potential therapeutic tool for repairing bone defects. In this study, we demonstrated the pro-osteogenic effects of exosomes derived form osteogenic differentiated BMSCs (OBMSC) and presented a novel exosmes-functionalized decellularized fish scale (DE-FS) scaffold for promoting bone regeneration in vivo. The DE-FS scaffolds were obtained through decellularization and decalcification processes, which exhibited high biocompatibility and low immunological rejection. The intrinsic anisotropic structures of DE-FS could enhance the adhesion and proliferation ability of BMSCs in vitro. In addition, we demonstrated that the porous structure of DE-FS endowed them with the capacity to load and release exosomes to BMSCs, resulting in the enhanced osteogenic differentiation of BMSCs. Concerning these pro-osteogenic effects, it was further proved that OBMSC exosome-modified DE-FS scaffolds could effectively promote bone regeneration in the mouse calvarial defect models. In conclusion, our work provided a new insight to design exosome-riched biomimetic scaffolds for bone tissue engineering and clinical applications.

Sustained release ketamine-loaded porous silicon-PLGA microparticles prepared by an optimized supercritical CO2 process

Ketamine in sub-anaesthetic doses has analgesic properties and an opioid-sparing effect. Intrathecal (i.t.) delivery of analgesics bypasses systemic metabolism and delivers the analgesic agent adjacent to the target receptors in the spinal cord and so small doses are required to achieve effective pain relief. In order to relieve intractable cancer-related pain, sustained-release ketamine formulations are required in combination with a strong opioid because frequent i.t. injection is not practical. In this study, ketamine or ketamine-loaded porous silicon (pSi) were encapsulated into poly(lactic-co-glycolic acid) (PLGA) microparticles by a novel supercritical carbon dioxide (scCO2) method, thereby avoiding the use of organic solvent. Multiple parameters including theoretical drug loading (DL), presence of pSi, size of scCO2 vessel, PLGA type, and use of co-solvent were investigated with a view to obtaining high DL and a sustained-release for an extended period. The most important finding was that the use of a large scCO2 vessel (60 mL) resulted in a much higher encapsulation efficiency (EE) compared with a small vessel (12 mL). In addition, pre-loading ketamine into pSi slightly improved the level of drug incorporation (i.e. EE and DL). Although the in vitro release was mainly affected by the drug payload, the use of the large scCO2 vessel reduced the burst release and extended the release period for PLGA microparticles with 10% or 20% ketamine loading. Together, our findings provide valuable information for optimization of drug delivery systems prepared with the aid of scCO2.

Recent advances in porous microneedles: materials, fabrication, and transdermal applications

In the past two decades, microneedles (MNs), as a painless and simple drug delivery system, have received increasing attention for various biomedical applications such as transdermal drug delivery, interstitial fluid (ISF) extraction, and biosensing. Among the various types of MNs, porous MNs have been recently researched owing to their distinctive and unique characteristics, where porous structures inside MNs with continuous nano- or micro-sized pores can transport drugs or biofluids by capillary action. In addition, a wide range of materials, including non-polymers and polymers, were researched and used to form the porous structures of porous MNs. Adjustable porosity by different fabrication methods enables the achievement of sufficient mechanical strength by optimising fluid flows inside MNs. Moreover, biocompatible porous MNs integrated with biosensors can offer portable detection and rapid measurement of biomarkers in a minimally invasive manner. This review focuses on several aspects of current porous MN technology, including material selection, fabrication processes, biomedical applications, primarily covering transdermal drug delivery, ISF extraction, and biosensing, along with future prospects as well as challenges.

Behaviour of Vascular Smooth Muscle Cells on Amine Plasma-Coated Materials with Various Chemical Structures and Morphologies

Amine-coated biodegradable materials based on synthetic polymers have a great potential for tissue remodeling and regeneration because of their excellent processability and bioactivity. In the present study, we have investigated the influence of various chemical compositions of amine plasma polymer (PP) coatings and the influence of the substrate morphology, represented by polystyrene culture dishes and polycaprolactone nanofibers (PCL NFs), on the behavior of vascular smooth muscle cells (VSMCs). Although all amine-PP coatings improved the initial adhesion of VSMCs, 7-day long cultivation revealed a clear preference for the coating containing about 15 at.% of nitrogen (CPA-33). The CPA-33 coating demonstrated the ideal combination of good water stability, a sufficient amine group content, and favorable surface wettability and morphology. The nanostructured morphology of amine-PP-coated PCL NFs successfully slowed the proliferation rate of VSMCs, which is essential in preventing restenosis of vascular replacements in vivo. At the same time, CPA-33-coated PCL NFs supported the continuous proliferation of VSMCs during 7-day long cultivation, with no significant increase in cytokine secretion by RAW 264.7 macrophages. The CPA-33 coating deposited on biodegradable PCL NFs therefore seems to be a promising material for manufacturing small-diameter vascular grafts, which are still lacking on the current market.

GATA4-targeted compound exhibits cardioprotective actions against doxorubicin-induced toxicity in vitro and in vivo: establishment of a chronic cardiotoxicity model using human iPSC-derived cardiomyocytes

Doxorubicin is a widely used anticancer drug that causes dose-related cardiotoxicity. The exact mechanisms of doxorubicin toxicity are still unclear, partly because most in vitro studies have evaluated the effects of short-term high-dose doxorubicin treatments. Here, we developed an in vitro model of long-term low-dose administration of doxorubicin utilizing human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Moreover, given that current strategies for prevention and management of doxorubicin-induced cardiotoxicity fail to prevent cancer patients developing heart failure, we also investigated whether the GATA4-targeted compound 3i-1000 has cardioprotective potential against doxorubicin toxicity both in vitro and in vivo. The final doxorubicin concentration used in the chronic toxicity model in vitro was chosen based on cell viability data evaluation. Exposure to doxorubicin at the concentrations of 1–3 µM markedly reduced (60%) hiPSC-CM viability already within 48 h, while a 14-day treatment with 100 nM doxorubicin concentration induced only a modest 26% reduction in hiPCS-CM viability. Doxorubicin treatment also decreased DNA content in hiPSC-CMs. Interestingly, the compound 3i-1000 attenuated doxorubicin-induced increase in pro-B-type natriuretic peptide (proBNP) expression and caspase-3/7 activation in hiPSC-CMs. Moreover, treatment with 3i-1000 for 2 weeks (30 mg/kg/day, i.p.) inhibited doxorubicin cardiotoxicity by restoring left ventricular ejection fraction and fractional shortening in chronic in vivo rat model. In conclusion, the results demonstrate that long-term exposure of hiPSC-CMs can be utilized as an in vitro model of delayed doxorubicin-induced toxicity and provide in vitro and in vivo evidence that targeting GATA4 may be an effective strategy to counteract doxorubicin-induced cardiotoxicity.

Crystallisation Behaviour of Pharmaceutical Compounds Confined within Mesoporous Silicon

The poor aqueous solubility of new and existing drug compounds represents a significant challenge in pharmaceutical development, with numerous strategies currently being pursued to address this issue. Amorphous solids lack the repeating array of atoms in the structure and present greater free energy than their crystalline counterparts, which in turn enhances the solubility of the compound. The loading of drug compounds into porous materials has been described as a promising approach for the stabilisation of the amorphous state but is dependent on many factors, including pore size and surface chemistry of the substrate material. This review looks at the applications of mesoporous materials in the confinement of pharmaceutical compounds to increase their dissolution rate or modify their release and the influence of varying pore size to crystallise metastable polymorphs. We focus our attention on mesoporous silicon, due to the ability of its surface to be easily modified, enabling it to be stabilised and functionalised for the loading of various drug compounds. The use of neutron and synchrotron X-ray to examine compounds and the mesoporous materials in which they are confined is also discussed, moving away from the conventional analysis methods.

Fabrication and Characterization of Drug-Loaded Conductive Poly(glycerol sebacate)/Nanoparticle-Based Composite Patch for Myocardial Infarction Applications

Heart tissue engineering is critical in the treatment of myocardial infarction, which may benefit from drug-releasing smart materials. In this study, we load a small molecule (3i-1000) in new biodegradable and conductive patches for application in infarcted myocardium. The composite patches consist of a biocompatible elastomer, poly(glycerol sebacate) (PGS), coupled with collagen type I, used to promote cell attachment. In addition, polypyrrole is incorporated because of its electrical conductivity and to induce cell signaling. Results from the in vitro experiments indicate a high density of cardiac myoblast cells attached on the patches, which stay viable for at least 1 month. The degradation of the patches does not show any cytotoxic effect, while 3i-1000 delivery induces cell proliferation. Conductive patches show high blood wettability and drug release, correlating with the rate of degradation of the PGS matrix. Together with the electrical conductivity and elongation characteristics, the developed biomaterial fits the mechanical, conductive, and biological demands required for cardiac treatment.

Osteogenic activity of a titanium surface modified with silicon-doped titanium dioxide

Titanium and its alloys are the most widely used implants in clinical practice. However, their bioactivity is unsatisfactory, and the effect of osteogenesis on the bonding interface between the implant and bone needs to be further improved. In this study, a coating consisting of microporous titanium doped with silicon (Si-TiO₂) was successfully created by microarc oxidation (MAO), and Si was evenly distributed on the surface of the coating. The surface morphology, roughness, and phase composition of the Si-TiO₂ microporous coating were similar to those of the Si-free doped MAO coatings. The Si-TiO₂ microporous coating can promote osteoblast adhesion, spreading, proliferation and differentiation. More importantly, the integrin β1-FAK signaling pathway may be involved in the regulatory effect of the coating on osteoblasts. Further studies in vivo indicated that the Si-TiO₂ microporous coating could improve early stage osseointegration. In conclusion, the Si-TiO₂ microporous coating is a feasible way to improve the osteogenic abilities of Ti implants to potentially promote clinical performance.

Introductory lecture: origins and applications of efficient visible photoluminescence from silicon-based nanostructures

This review highlights many spectroscopy-based studies and selected phenomenological studies of silicon-based nanostructures that provide insight into their likely PL mechanisms, and also covers six application areas.

Engineered antibody-functionalized porous silicon nanoparticles for therapeutic targeting of pro-survival pathway in endogenous neuroblasts after stroke

Generation of new neurons by utilizing the regenerative potential of adult neural stem cells (NSCs) and neuroblasts is an emerging therapeutic strategy to treat various neurodegenerative diseases, including neuronal loss after stroke. Committed to neuronal lineages, neuroblasts are differentiated from NSCs and have a lower proliferation rate. In stroke the proliferation of the neuroblasts in the neurogenic areas is increased, but the limiting factor for regeneration is the poor survival of migrating neuroblasts. Survival of neuroblasts can be promoted by small molecules; however, new drug delivery methods are needed to specifically target these cells. Herein, to achieve specific targeting, we have engineered biofunctionalized porous silicon nanoparticles (PSi NPs) conjugated with a specific antibody against polysialylated neural cell adhesion molecule (PSA-NCAM). The PSi NPs loaded with a small molecule drug, SC-79, were able to increase the activity of the Akt signaling pathway in doublecortin positive neuroblasts both in cultured cells and in vivo in the rat brain. This study opens up new possibilities to target drug effects to migrating neuroblasts and facilitate differentiation, maturation and survival of developing neurons. The conjugated PSi NPs are a novel tool for future studies to develop new therapeutic strategies aiming at regenerating functional neurocircuitry after stoke.

Electrically Conductive Materials: Opportunities and Challenges in Tissue Engineering

Tissue engineering endeavors to regenerate tissues and organs through appropriate cellular and molecular interactions at biological interfaces. To this aim, bio-mimicking scaffolds have been designed and practiced to regenerate and repair dysfunctional tissues by modifying cellular activity. Cellular activity and intracellular signaling are performances given to a tissue as a result of the function of elaborated electrically conductive materials. In some cases, conductive materials have exhibited antibacterial properties; moreover, such materials can be utilized for on-demand drug release. Various types of materials ranging from polymers to ceramics and metals have been utilized as parts of conductive tissue engineering scaffolds, having conductivity assortments from a range of semi-conductive to conductive. The cellular and molecular activity can also be affected by the microstructure; therefore, the fabrication methods should be evaluated along with an appropriate selection of conductive materials. This review aims to address the research progress toward the use of electrically conductive materials for the modulation of cellular response at the material-tissue interface for tissue engineering applications.

Porous Silicon as a Platform for Radiation Theranostics Together with a Novel RIB-Based Radiolanthanoid

Mesoporous silicon (PSi) is biocompatible and tailorable material with high potential in drug delivery applications. Here, we report of an evaluation of PSi as a carrier platform for theranostics by delivering a radioactive ion beam- (RIB-) based radioactive lanthanoid into tumors in a mouse model of prostate carcinoma. Thermally hydrocarbonized porous silicon (THCPSi) wafers were implanted with 159Dy at the facility for radioactive ion beams ISOLDE located at CERN, and the resulting [159Dy]THCPSi was postprocessed into particles. The particles were intratumorally injected into mice bearing prostate cancer xenografts. The stability of the particles was studied in vivo, followed by ex vivo biodistribution and autoradiographic studies. We showed that the process of producing radionuclide-implanted PSi particles is feasible and that the [159Dy]THCPSi particles stay stable and local inside the tumor over seven days. Upon release of 159Dy from the particles, the main site of accumulation is in the skeleton, which is in agreement with previous studies on the biodistribution of dysprosium. We conclude that THCPSi particles are a suitable platform together with RIB-based radiolanthanoids for theranostic purposes as they are retained after administration inside the tumor and the radiolanthanoid remains embedded in the THCPSi.

Spatially Controlled Surface Modification of Porous Silicon for Sustained Drug Delivery Applications

A new and facile approach to selectively functionalize the internal and external surfaces of porous silicon (pSi) for drug delivery applications is reported. To provide a surface that is suitable for sustained drug release of the hydrophobic cancer chemotherapy drug camptothecin (CPT), the internal surfaces of pSi films were first modified with 1-dodecene. To further modify the external surface of the pSi samples, an interlayer was applied by silanization with (3-aminopropyl)triethoxysilane (APTES) following air plasma treatment. In addition, copolymers of N-(2-hydroxypropyl) acrylamide (HPAm) and N-benzophenone acrylamide (BPAm) were grafted onto the external pSi surfaces by spin-coating and UV crosslinking. Each modification step was verified using attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, water contact angle (WCA) measurements, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). In order to confirm that the air plasma treatment and silanization step only occurred on the top surface of pSi samples, confocal microscopy was employed after fluorescein isothiocyanate (FITC) conjugation. Drug release studies carried out over 17 h in PBS demonstrated that the modified pSi reservoirs released CPT continuously, while showing excellent stability. Furthermore, protein adsorption and cell attachment studies demonstrated the ability of the graft polymer layer to reduce both significantly. In combination with the biocompatible pSi substrate material, the facile modification strategy described in this study provides access to new multifunctional drug delivery systems (DDS) for applications in cancer therapy.

Cellular Internalization-Induced Aggregation of Porous Silicon Nanoparticles for Ultrasound Imaging and Protein-Mediated Protection of Stem Cells

Nanotechnology employs multifunctional engineered materials in the nanoscale range that provides many opportunities for translational stem cell research and therapy. Here, a cell-penetrating peptide (virus-1 transactivator of transcription)-conjugated, porous silicon nanoparticle (TPSi NP) loaded with the Wnt3a protein to increase both the cell survival rate and the delivery precision of stem cell transplantation via a combinational theranostic strategy is presented. The TPSi NP with a pore size of 10.7 nm and inorganic framework enables high-efficiency loading of Wnt3a, prolongs Wnt3a release, and increases antioxidative stress activity in the labeled mesenchymal stem cells (MSCs), which are highly beneficial properties for cell protection in stem cell therapy for myocardial infarction. It is confirmed that the intracellular aggregation of TPSi NPs can highly amplify the acoustic scattering of the labeled MSCs, resulting in a 2.3-fold increase in the ultrasound (US) signal compared with that of unlabeled MSCs. The translational potential of the designed nanoagent for real-time US imaging-guided stem cell transplantation is confirmed via intramyocardial injection of labeled MSCs in a nude mouse model. It is proposed that the intracellular aggregation of protein drug-loaded TPSi NPs could be a simple but robust strategy for improving the therapeutic effect of stem cell therapy.

Nanoparticles for postinfarct ventricular remodeling

In recent years, tremendous progress has been made in the treatment of acute myocardial infarction, but pathological ventricular remodeling often causes survivors to suffer from fatal heart failure. Currently, there is no effective therapy to attenuate ventricular remodeling. Recently, nanoparticle-based drug delivery systems are widely applied in biomedicine especially in cancer and liver fibrosis, owing to its excellent physical, chemical and biological properties. Therefore, the use of nanoparticles as delivery vehicles of small molecules, polypeptides, etc. to improve postinfarct ventricular remodeling is expected. In this review, we summarize the updated researches in this fast-growing area and suggest further works needed.

Designed inorganic porous nanovector with controlled release and MRI features for safe administration of doxorubicin

The inability of traditional chemotherapeutics to reach cancer tissue reduces the treatment efficacy and leads to adverse effects. A multifunctional nanovector was developed consisting of porous silicon, superparamagnetic iron oxide, calcium carbonate, doxorubicin and polyethylene glycol. The particles integrate magnetic properties with the capacity to retain drug molecules inside the pore matrix at neutral pH to facilitate drug delivery to tumor tissues. The MRI applicability and pH controlled drug release were examined in vitro together with in-depth material characterization. The in vivo biodistribution and compound safety were verified using A549 lung cancer bearing mice before proceeding to therapeutic experiments using CT26 cancer implanted mice. Loading doxorubicin into the porous nanoparticle negated the adverse side effects encountered after intravenous administration highlighting the particles' excellent biocompatibility. Furthermore, the multifunctional nanovector induced 77% tumor reduction after intratumoral injection. The anti-tumor effect was comparable with that of free doxorubicin but with significantly alleviated unwanted effects. These results demonstrate that the developed porous silicon-based nanoparticles represent promising multifunctional drug delivery vectors for cancer monitoring and therapy.

Mesoporous Silicon Particles Favor the Induction of Long-Lived Humoral Responses in Mice to a Peptide-Based Vaccine

Vaccinology faces the challenge of developing improved immunization approaches that are able to induce long-term immunity with the desired Th profile according to the pathology. In this context, new vehicles for efficient antigen delivery that exert adjuvant effects play a critical role in addressing this goal. Herein, mesoporous silicon particles (PSiP) were assessed as carriers for a peptide-based vaccine targeting the receptor for advanced glycation end products (RAGE), which is a relevant receptor in Alzheimer´s disease and other diseases. A RAGE peptide was adsorbed onto PSiP (PSiP vaccine) and administered to BALB/c mice, leading to immune responses that were similar in magnitude to those induced by the soluble peptide. However, the response induced by PSiP lasted for a significantly longer period when compared with the behavior of the group immunized with the peptide alone. Therefore, PSiP are proposed as carriers to enhance immune memory, which is critical in vaccination. This study opens interesting perspectives related to the application of PSiP in vaccinology.

Multimodality Imaging of Silica and Silicon Materials In Vivo

Recent progress in the development of silica- and silicon-based multimodality imaging nanoprobes has advanced their use in image-guided drug delivery, and the development of novel systems for nanotheranostic and diagnostic applications. As biocompatible and flexibly tunable materials, silica and silicon provide excellent platforms with high clinical potential in nanotheranostic and diagnostic probes with well-defined morphology and surface chemistry, yielding multifunctional properties. In vivo imaging is of great value in the exploration of methods for improving site-specific nanotherapeutic delivery by silica- and silicon-based drug-delivery systems. Multimodality approaches are essential for understanding the biological interactions of nanotherapeutics in the physiological environment in vivo. The aim here is to describe recent advances in the development of in vivo imaging tools based on nanostructured silica and silicon, and their applications in single and multimodality imaging.

Tailoring Porous Silicon for Biomedical Applications: From Drug Delivery to Cancer Immunotherapy

In the past two decades, porous silicon (PSi) has attracted increasing attention for its potential biomedical applications. With its controllable geometry, tunable nanoporous structure, large pore volume/high specific surface area, and versatile surface chemistry, PSi shows significant advantages over conventional drug carriers. Here, an overview of recent progress in the use of PSi in drug delivery and cancer immunotherapy is presented. First, an overview of the fabrication of PSi with various geometric structures is provided, with particular focus on how the unique geometry of PSi facilitates its biomedical applications, especially for drug delivery. Second, surface chemistry and modification of PSi are discussed in relation to the strengthening of its performance in drug delivery and bioimaging. Emerging technologies for engineering PSi-based composites are then summarized. Emerging PSi advances in the context of cancer immunotherapy are also highlighted. Overall, very promising research results encourage further exploration of PSi for biomedical applications, particularly in drug delivery and cancer immunotherapy, and future translation of PSi into clinical applications.

Thermally Carbonized Porous Silicon and Its Recent Applications

Recent progress in research on thermally carbonized porous silicon (TCPSi) and its applications is reported. Despite a slow start, thermal carbonization has now started to gain interest mainly due to new emerging areas for applications. These new areas, such as optical sensing, drug delivery, and energy storage, require stable surface chemistry and physical properties. TCPSi is known to have all of these desired properties. Herein, the above-listed properties of TCPSi are summarized, and the carbonization processes, functionalization, and characterization of TCPSi are reviewed. Moreover, some of the emerging fields of TCPSi applications are discussed and recent advances in the fields are introduced.

Cardiac Actions of a Small Molecule Inhibitor Targeting GATA4-NKX2-5 Interaction

Transcription factors are fundamental regulators of gene transcription, and many diseases, such as heart diseases, are associated with deregulation of transcriptional networks. In the adult heart, zinc-finger transcription factor GATA4 is a critical regulator of cardiac repair and remodelling. Previous studies also suggest that NKX2-5 plays function role as a cofactor of GATA4. We have recently reported the identification of small molecules that either inhibit or enhance the GATA4–NKX2-5 transcriptional synergy. Here, we examined the cardiac actions of a potent inhibitor (3i-1000) of GATA4–NKX2-5 interaction in experimental models of myocardial ischemic injury and pressure overload. In mice after myocardial infarction, 3i-1000 significantly improved left ventricular ejection fraction and fractional shortening, and attenuated myocardial structural changes. The compound also improved cardiac function in an experimental model of angiotensin II -mediated hypertension in rats. Furthermore, the up-regulation of cardiac gene expression induced by myocardial infarction and ischemia reduced with treatment of 3i-1000 or when micro- and nanoparticles loaded with 3i-1000 were injected intramyocardially or intravenously, respectively. The compound inhibited stretch- and phenylephrine-induced hypertrophic response in neonatal rat cardiomyocytes. These results indicate significant potential for small molecules targeting GATA4–NKX2-5 interaction to promote myocardial repair after myocardial infarction and other cardiac injuries.

Biodegradation of inorganic drug delivery systems in subcutaneous conditions

Despite extensive efforts to develop delivery systems for oral administration, subcutaneous (s.c.) injection remains the most common way to administer peptide drugs. To limit the number of frequent injections, sustained release systems that are easy to produce, suitable for various drugs, safe and biodegradable are urgently needed. Porous silicon (PSi) has been recognized to be one of the most promising materials for s.c. peptide delivery, but its biodegradation in s.c. tissue has not been studied in vivo, despite extensive in vitro research. In the present study, differently modified PSi microparticles were injected s.c. in mice, after which the morphology of the particles was thoroughly studied with transmission electron microscopy, micro-computed tomography and X-ray diffraction. Furthermore, histopathology of the s.c. tissue was analyzed to evaluate biocompatibility. To the best of our knowledge, this is the first systematic study which reveals the degradation behavior of various PSi materials in vivo. The PSi surface chemistry significantly affected the biodegradation rate of the s.c. injected microparticles. The most hydrophobic PSi microparticles with hydrocarbonized surface showed the lowest biodegradation rate while the hydrophilic microparticles, with oxide surface, degraded the fastest. The results from different empirical methods complemented each other to deduce the biodegradation mechanism of the inorganic delivery system, providing useful information for future development of s.c. carriers.

A novel ventricular restraint device (ASD) repetitively deliver Salvia miltiorrhiza to epicardium have good curative effects in heart failure management

A novel ventricular restraint is the non-transplant surgical option for the management of an end-stage dilated heart failure (HF). To expand the therapeutic techniques we design a novel ventricular restraint device (ASD) which has the ability to deliver a therapeutic drug directly to the heart. We deliver a Traditional Chinese Medicine (TCM) Salvia miltiorrhiza (Danshen Zhusheye) through active hydraulic ventricular support drug delivery system (ASD) and we hypothesize that it will show better results in HF management than the restraint device and drug alone. SD rats were selected and divided into five groups (n=6), Normal, HF, HF+SM (IV), HF+ASD, HF+ASD+SM groups respectively. Post myocardial infarction (MI), electrocardiography (ECG) showed abnormal heart function in all groups and HF+ASD+SM group showed a significant therapeutic improvement with respect to other treatment HF, HF+ASD, and HF+SM (IV) groups on day 30. The mechanical functions of the heart such as heart rate, LVEDP, and LVSP were brought to normal when treated with ASD+SM and show significant (P value<0.01) compared to other groups. BNP significantly declines in HF+ASD+SM group animals compared with other treatment groups. Masson's Trichrome staining was used to study histopathology of cardiac myocytes and quantification of fibrosis was assessed. The large blue fibrotic area was observed in HF, HF+ASD, and HF+SM (IV) groups while HF+ASD+SM showed negligible fibrotic myocyte at the end of study period (30days). This study proves that novel ASD device augments the therapeutic effect of the drug and delivers Salvia miltiorrhiza to the cardiomyocytes significantly as well as provides additional support to the dilated ventricle by the heart failure.

Drug-Loaded Multifunctional Nanoparticles Targeted to the Endocardial Layer of the Injured Heart Modulate Hypertrophic Signaling

Ischemic heart disease is the leading cause of death globally. Severe myocardial ischemia results in a massive loss of myocytes and acute myocardial infarction, the endocardium being the most vulnerable region. At present, current therapeutic lines only ameliorate modestly the quality of life of these patients. Here, an engineered nanocarrier is reported for targeted drug delivery into the endocardial layer of the left ventricle for cardiac repair. Biodegradable porous silicon (PSi) nanoparticles are functionalized with atrial natriuretic peptide (ANP), which is known to be expressed predominantly in the endocardium of the failing heart. The ANP-PSi nanoparticles exhibit improved colloidal stability and enhanced cellular interactions with cardiomyocytes and non-myocytes with minimal toxicity. After confirmation of good retention of the radioisotope 111-Indium in relevant physiological buffers over 4 h, in vivo single-photon emission computed tomography (SPECT/CT) imaging and autoradiography demonstrate increased accumulation of ANP-PSi nanoparticles in the ischemic heart, particularly in the endocardial layer of the left ventricle. Moreover, ANP-PSi nanoparticles loaded with a novel cardioprotective small molecule attenuate hypertrophic signaling in the endocardium, demonstrating cardioprotective potential. These results provide unique insights into the development of nanotherapies targeted to the injured region of the myocardium.

Cell number per spheroid and electrical conductivity of nanowires influence the function of silicon nanowired human cardiac spheroids

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) provide an unlimited cell source to treat cardiovascular diseases, the leading cause of death worldwide. However, current hiPSC-CMs retain an immature phenotype that leads to difficulties for integration with adult myocardium after transplantation. To address this, we recently utilized electrically conductive silicon nanowires (e-SiNWs) to facilitate self-assembly of hiPSC-CMs to form nanowired hiPSC cardiac spheroids. Our previous results showed addition of e-SiNWs effectively enhanced the functions of the cardiac spheroids and improved the cellular maturation of hiPSC-CMs. Here, we examined two important factors that can affect functions of the nanowired hiPSC cardiac spheroids: (1) cell number per spheroid (i.e., size of the spheroids), and (2) the electrical conductivity of the e-SiNWs. To examine the first factor, we prepared hiPSC cardiac spheroids with four different sizes by varying cell number per spheroid (∼0.5k, ∼1k, ∼3k, ∼7k cells/spheroid). Spheroids with ∼3k cells/spheroid was found to maximize the beneficial effects of the 3D spheroid microenvironment. This result was explained with a semi-quantitative theory that considers two competing factors: 1) the improved 3D cell-cell adhesion, and 2) the reduced oxygen supply to the center of spheroids with the increase of cell number. Also, the critical role of electrical conductivity of silicon nanowires has been confirmed in improving tissue function of hiPSC cardiac spheroids. These results lay down a solid foundation to develop suitable nanowired hiPSC cardiac spheroids as an innovative cell delivery system to treat cardiovascular diseases.

STATEMENT OF SIGNIFICANCE

Cardiovascular disease is the leading cause of death and disability worldwide. Due to the limited regenerative capacity of adult human hearts, human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have received significant attention because they provide a patient specific cell source to regenerate damaged hearts. Despite the progress, current human hiPSC-CMs retain an immature phenotype that leads to difficulties for integration with adult myocardium after transplantation. To address this, we recently utilized electrically conductive silicon nanowires (e-SiNWs) to facilitate self-assembly of hiPSC-CMs to form nanowired hiPSC cardiac spheroids. Our previous results showed addition of e-SiNWs effectively enhanced the functions of the cardiac spheroids and improved the cellular maturation of hiPSC-CMs. In this manuscript, we examined the effects of two important factors on the functions of nanowired hiPSC cardiac spheroids: (1) cell number per spheroid (i.e., size of the spheroids), and (2) the electrical conductivity of the e-SiNWs. The results from these studies will allow for the development of suitable nanowired hiPSC cardiac spheroids to effectively deliver hiPSC-CMs for heart repair.

Mammalian fibroblast cells show strong preference for laser-generated hybrid amorphous silicon-SiO2 textures

BACKGROUND

In this study, we investigated a method to produce bioactive hybrid amorphous silicon and silicon oxide patterns using nanosecond laser pulses.

METHODS

Microscale line patterns were made by laser pulses on silicon wafers at different frequencies (25, 70 and 100 kHz), resulting in ablation patterns with frequency-dependent physical and chemical properties.

RESULTS

Incubating the laser-treated silicon substrates with simulated body fluid demonstrated that the physicochemical properties of the laser-treated samples were stable under these conditions, and favored the deposition of bone-like apatite. More importantly, while NIH 3T3 fibroblasts did colonize the untreated regions of the silicon wafers, they showed a strong preference for the laser-treated regions, and further discriminated between substrates treated with different frequencies.

CONCLUSIONS

Taken together, these data suggest that laser materials processing of silicon-based devices is a promising avenue to pursue in the production of biosensors and other bionic devices.

Exo-organoplasty interventions: A brief review of past, present and future directions for advance heart failure management

Heart failure (HF) is a debilitating disease in which abnormal function of the heart leads to imbalance of blood demand to tissues and organs. The pathogenesis of HF is very complex and various factors can contribute including myocardial infarction, ischemia, hypertension and genetic cardiomyopathies. HF is the leading cause of death and its prevalence is expected to increase in parallel with the population age. Different kind of therapeutic approaches including lifestyle modification, medication and pacemakers are used for HF patients in NYHA I-III functional class. However, for advance stage HF patient's (NYHA IV), ventricle assist devices are clinically use and stem cells are under active investigation. Most of these therapies leads to modest symptoms relief and have no significant role in long-term survival rate. Currently there is no effective treatment for advance HF except heart transplantation, which is still remain clinically insignificant because of donor pool limitation. As HF is a result of multiple etiologies therefore multi-functional therapeutic platform is needed. Exo-organoplasty interventions are studied from almost one century. The major goals of these interventions are to treat various kind of heart disease from outside the heart muscle without having direct contact with blood. Various kind of interventions (devices and techniques) are developed in this arena with the passage of time. The purpose of this review is to describe the theory behind intervention devices, the devices themselves, their clinical results, advantages and limitations. Furthermore, to present a future multi-functional therapeutic platform (ASD) for advance stage HF management.

Role of porous silicon/hydrogel composites on drug delivery

Nanomaterials are applied with great success in biomedical applications as templates for the development of new generation devices, which can be used to solve current health problems. These new nanoscale systems are designed with multifunctions to perform specific and selective tasks. One of the most important applications of this new nanotechnology; focuses on developing new systems for the controlled release of drugs, mainly due to their capability to improve the temporal and spatial presentation of drugs in the body and their ability to protect them from physiological degradation or elimination. Hydrogels, porous silicon (PSi), and PSi-composites have been widely adopted in this field due to their biological, morphological, and physicochemical properties; which can be tuned to obtain sensitive responses to physiological stimuli. Despite the fact that some recent academic papers have shown the benefits of these nanomaterials in a wide range of biological applications, more in vivo studies are needed to take these hybrid systems towards clinical trials. In this mini-review some of the hydrogels, PSi, and PSi-composites latest applications and prospects in this field of science are presented.

Active diffusion of nanoparticles of maternal origin within the embryonic brain

Aim: To investigate porous silicon (PSi) nanoparticles (NPs) behavior in the embryonic brain. Materials & methods: Fluorescently labeled PSi NPs were injected into the embryonic brains intraventricularly and to the mother intravenously (iv.). Brain histology from different time points up to 3 days was analyzed and live brains imaged with two-photon microscopy. Results: PSi NPs were able to penetrate 80% of the embryonic cortical depth. Particle motility was confirmed in real-time in vivo. PSi NPs were able to penetrate the embryonic cortex after either iv. maternal or intraventricular injection. No developmental of macromorphological changes or increased cell apoptosis was observed. Conclusion: PSi NPs penetrate deep in the brain tissues of embryos after intraventricular injection and after iv. injection to the mother.

Nanowires and Electrical Stimulation Synergistically Improve Functions of hiPSC Cardiac Spheroids

The advancement of human induced pluripotent stem-cell-derived cardiomyocyte (hiPSC-CM) technology has shown promising potential to provide a patient-specific, regenerative cell therapy strategy to treat cardiovascular disease. Despite the progress, the unspecific, underdeveloped phenotype of hiPSC-CMs has shown arrhythmogenic risk and limited functional improvements after transplantation. To address this, tissue engineering strategies have utilized both exogenous and endogenous stimuli to accelerate the development of hiPSC-CMs. Exogenous electrical stimulation provides a biomimetic pacemaker-like stimuli that has been shown to advance the electrical properties of tissue engineered cardiac constructs. Recently, we demonstrated that the incorporation of electrically conductive silicon nanowires to hiPSC cardiac spheroids led to advanced structural and functional development of hiPSC-CMs by improving the endogenous electrical microenvironment. Here, we reasoned that the enhanced endogenous electrical microenvironment of nanowired hiPSC cardiac spheroids would synergize with exogenous electrical stimulation to further advance the functional development of nanowired hiPSC cardiac spheroids. For the first time, we report that the combination of nanowires and electrical stimulation enhanced cell-cell junction formation, improved development of contractile machinery, and led to a significant decrease in the spontaneous beat rate of hiPSC cardiac spheroids. The advancements made here address critical challenges for the use of hiPSC-CMs in cardiac developmental and translational research and provide an advanced cell delivery vehicle for the next generation of cardiac repair.

In vitro and in vivo assessment of heart-homing porous silicon nanoparticles

Chronic heart failure, predominantly developed after myocardial infarction, is a leading cause of high mortality worldwide. As existing therapies have still limited success, natural and/or synthetic nanomaterials are emerging alternatives for the therapy of heart diseases. Therefore, we aimed to functionalize undecylenic acid thermally hydrocarbonized porous silicon nanoparticles (NPs) with different targeting peptides to improve the NP's accumulation in different cardiac cells (primary cardiomyocytes, non-myocytes, and H9c2 cardiomyoblasts), additionally to investigate the behavior of the heart-targeted NPs in vivo. The toxicity profiles of the NPs evaluated in the three heart-type cells showed low toxicity at concentrations up to 50 μg/mL. Qualitative and quantitative cellular uptake revealed a significant increase in the accumulation of atrial natriuretic peptide (ANP)-modified NPs in primary cardiomyocytes, non-myocytes and H9c2 cells, and in hypoxic primary cardiomyocytes and non-myocytes. Competitive uptake studies in primary cardiomyocytes showed the internalization of ANP-modified NPs takes place via the guanylate cyclase-A receptor. When a myocardial infarction rat model was induced by isoprenaline and the peptide-modified [(111)In]NPs administered intravenously, the targeting peptides, particularly peptide 2, improved the NPs' accumulation in the heart up to 3.0-fold, at 10 min. This study highlights the potential of these peptide-modified nanosystems for future applications in heart diseases.

Towards comprehensive cardiac repair and regeneration after myocardial infarction: Aspects to consider and proteins to deliver

Ischemic heart disease is a leading cause of death worldwide. After the onset of myocardial infarction, many pathological changes take place and progress the disease towards heart failure. Pathologies such as ischemia, inflammation, cardiomyocyte death, ventricular remodeling and dilation, and interstitial fibrosis, develop and involve the signaling of many proteins. Proteins can play important roles in limiting or countering pathological changes after infarction. However, they typically have short half-lives in vivo in their free form and can benefit from the advantages offered by controlled release systems to overcome their challenges. The controlled delivery of an optimal combination of proteins per their physiologic spatiotemporal cues to the infarcted myocardium holds great potential to repair and regenerate the heart. The effectiveness of therapeutic interventions depends on the elucidation of the molecular mechanisms of the cargo proteins and the spatiotemporal control of their release. It is likely that multiple proteins will provide a more comprehensive and functional recovery of the heart in a controlled release strategy.

In situ investigation of mesoporous silicon oxidation kinetics using infrared emittance spectroscopy

The kinetics of mesoporous silicon oxidation is investigated by means of infrared emittance measurements. The chemical mechanisms are put in perspective with temperature.

Silicon nanostructures for cancer diagnosis and therapy

The emergence of nanotechnology suggests new and exciting opportunities for early diagnosis and therapy of cancer. During the recent years, silicon-based nanomaterials featuring unique properties have received great attention, showing high promise for myriad biological and biomedical applications. In this review, we will particularly summarize latest representative achievements on the development of silicon nanostructures as a powerful platform for cancer early diagnosis and therapy. First, we introduce the silicon nanomaterial-based biosensors for detecting cancer markers (e.g., proteins, tumor-suppressor genes and telomerase activity, among others) with high sensitivity and selectivity under molecular level. Then, we summarize in vitro and in vivo applications of silicon nanostructures as efficient nanoagents for cancer therapy. Finally, we discuss the future perspective of silicon nanostructures for cancer diagnosis and therapy.

Silicon nanowire-induced maturation of cardiomyocytes derived from human induced pluripotent stem cells

The current inability to derive mature cardiomyocytes from human pluripotent stem cells has been the limiting step for transitioning this powerful technology into clinical therapies. To address this, scaffold-based tissue engineering approaches have been utilized to mimic heart development in vitro and promote maturation of cardiomyocytes derived from human pluripotent stem cells. While scaffolds can provide 3D microenvironments, current scaffolds lack the matched physical/chemical/biological properties of native extracellular environments. On the other hand, scaffold-free, 3D cardiac spheroids (i.e., spherical-shaped microtissues) prepared by seeding cardiomyocytes into agarose microwells were shown to improve cardiac functions. However, cardiomyocytes within the spheroids could not assemble in a controlled manner and led to compromised, unsynchronized contractions. Here, we show, for the first time, that incorporation of a trace amount (i.e., ∼0.004% w/v) of electrically conductive silicon nanowires (e-SiNWs) in otherwise scaffold-free cardiac spheroids can form an electrically conductive network, leading to synchronized and significantly enhanced contraction (i.e., >55% increase in average contraction amplitude), resulting in significantly more advanced cellular structural and contractile maturation.

Mesoporous silica nanoparticles for glutathione-triggered long-range and stable release of hydrogen sulfide

Mesoporous silica nanoparticles (MSNs) that can stably load therapeutic drugs and release them in response to a specific trigger are of great interest in disease diagnosis and treatment. However, the controlled-release of gaseous drug molecules such as hydrogen sulfide (H₂S) from a long-range and stable MSN-based system still presents a great challenge. Herein, a MSN-based glutathione (GSH)-triggered controlled-release H₂S system has been fabricated with high entrapment efficiency (99.0 ± 0.3%) and loading content (44.2 ± 0.1%) of diallyl trisulfide (DATS). After the addition of GSH (2 mM), DATS-MSN (100 μg mL^-1) steadily releases moderate amounts of H₂S (peaking at the 4th hour, ∼60 μM) in phosphate buffer solution (PBS). The release of H₂S in plasma is similar to a physiological process (peaking at the 4th hour) and the DATS-MSN remains in the plasma of a rat's system over 9 hours without significantly affecting the blood pressure, heart rate and cardiac function. Moderate quantities of nanoparticles can be taken up by cardiomyocytes in vitro, while in vivo study shows that nanoparticles mainly accumulate in the liver and spleen, affecting the H₂S level in these organs. Furthermore, DATS-MSN shows excellent biocompatibility, as well as superior cytoprotection and an isolated heart protection effect of H₂S under ischemic/reperfusion injury. This study provides a new insight into controlled-release applications of MSN-based H₂S releasing systems both in vitro and in vivo.

Porous silicon for cancer therapy: from fundamental research to the clinic

Porous silicon (PSi) has emerged over the past decade as a promising biomaterial for nanomedicine in general and cancer nanomedicine in particular. PSi offers a unique combination of properties, including large surface area and porous volume, biocompatibility, degradability

Boosting, probing and switching-off visible light-induced photocurrents in eumelanin-porous silicon hybrids

Improved solid state polymerization of eumelanin in porous silicon and new insights into the mechanisms of photoconduction of eumelanin films.